Apparatus for writing data bits to a memory array

ABSTRACT

A method of writing data bits to a memory array. In one method embodiment, a first input is received. This causes an application of high power, via a sense line, to an addressed bit in the memory array and causes a write operation to be applied to the addressed bit. A second input is received. This causes an application of low power, via said sense line, to the addressed bit and causes a read operation on the addressed bit. The sense line is used to read and write the addressed bit.

TECHNICAL FIELD

[0001] The present invention relates to a method and apparatus forwriting data bits to a memory array.

BACKGROUND ART

[0002] In nearly every electronic and computer device and/or system,there are memory components and elements which are used in conjunctionwith the storing of data/information. This data/information may be, butis not limited to, operating system instructions, currently used data,or data that is to be archived and retained within a memory component ordata storage device, and the like.

[0003] To provide for the storage of data that is to be archived,non-volatile data storage devices were developed to provide datastorage. Permanently stored data, commonly termed archived data, onlyneeds to be written once to memory, and can then be read many times. Oneexample of memory that can provide data storage is commonly referred toas WORM (write once read many) memory. Another example of memory thatcan provide data storage is rewriteable memory.

[0004] Unfortunately, previous data storage devices such as hard disks,floppies, and CD-RWs, etc., are now commonly larger in size than many ofthe handheld computer systems and digital devices so prevalent today.

[0005] Accordingly, to provide data storage for the more diminutivecomputers and digital devices, newer and smaller sized data storagedevices have been developed. Further, these newer data storage devicesneed to have storage capacities sufficient for the storing for digitalimages and digital audio.

[0006] One such data storage device recently developed is flash memory.One form of flash memory is that which is compatible with PCMCIAstandards. Another form of flash memory is that which is compatible witha Compact Flash card standards. In yet another form, the flash memory isvery similar in function to a miniature floppy disk, but with a muchgreater storage capacity. A floppy disk has a capacity of 1.44 MB(megabytes) whereas this form of flash memory can have a capacity thatranges from 8 MB up to 128 MB, or more, of storage space, which is morethan adequate for most images, audio files, and/or the archiving ofdata. This type of flash memory is commonly referred to as an SD (securedigital) card, an MMC (multi-media card), or a memory stick. This typeof flash memory is becoming more and more prevalent in today'selectronic devices, e.g., digital cameras, printers, MP3 players, PDA's,and the like.

[0007] The memory section of the flash memory is called the array, or acrosspoint array, or a crosspoint matrix. A crosspoint array or matrixis an arrangement of signal circuits in which input buses arerepresented by vertical parallel lines and output buses are representedas overlapping horizontal parallel lines. Crosspoint switches at each ofthe intersecting points connect the inputs with the outputs. Within thecrosspoint array, there are a multitude of memory cells. The number ofmemory cells is dependent upon the size of the array, and can range fromas few as a couple of hundred to millions or billions of memory cells.For an electronic device/system and/or a computer system to utilize thememory cells within a memory component, there exists a necessity to beable to read and write data bits to and from the memory cell.

[0008] It is commonly known that the writing of data bits can beaccomplished by a switching of the power supply voltage to asubstantially higher level. While this increase in power supply voltagedoes, in fact, enable the writing of data bits, it is not withoutcertain drawbacks. Because of the need to increase the power supplyvoltage to provide data bit writing functionality, numerous ways toprovide the increased power supply voltage have been attempted.

[0009] In one example, an additional power supply, separate from thefirst power supply, is implemented. The additional power supply uses aportion of the remaining critical real estate within the electronicdevice and additional power is needed to operate the additional powersupply. While the additional power supply enables data bit writing, byhaving to account for and to accommodate the power supply within theelectronic device, the size of electronic device into which it would beplaced may have to be increased, which can add to the overall cost ofthe device. Further, because the additional power supply requiresadditional power for it to operate, it may have a detrimental effectupon the capacity of the first power supply. This is especially criticalin those electronic devices where the power is derived from batteries orrechargeable power sources. By requiring additional power from thelimited retained energy source to power both power supplies, batteryreplacement or recharging can become more frequent.

[0010] In another attempt, a means to significantly change the output ofa single power supply is implemented. This is accomplished through theaddition of a variety of components and related circuitry, such asamplifiers, transistors, diodes, and the like. While enabling data bitwriting, it would, by virtue of the inherent propagation delays withineach of the additional components, be a slow-responding process.Additionally, the increase in required real estate to accommodate theadded components and circuitry could negatively impact the size of theelectronic device. Further, in most cases, the additional components andcircuitry would require additional power to be provided to ensure theirproper operation. As such, in electronic devices and computer systemsthat operate on batteries or a rechargeable power source, this couldcause an increase in the frequency with which the batteries are replacedor the power source is recharged.

[0011] Further, during the writing process, it is common to apply powerto the entire crosspoint array. While writing, power is beingunnecessarily wasted as only some of the memory cells within the arrayare written to at any one time. As such, when writing to an array inthis manner, where the electronic device or computer system is poweredby a battery or a rechargeable power source, this power waste may causean increase in the frequency with which battery or the rechargeablepower source is replaced or recharged, respectively.

[0012] Thus, it would be beneficial to be able to write a data bit to acell in a memory array where additional power sources are not required.It would also be beneficial to use existing components and circuitrywhen writing to a memory array. It would be further beneficial to writeto a cell in a memory array where power is applied to those portions ofthe array to which the data bit is being written.

DISCLOSURE OF THE INVENTION

[0013] Therefore, embodiments of the present invention are drawn toproviding a method and apparatus for writing data bits to a memoryarray.

[0014] In one method embodiment, a first input is received. This causesan application of high power, via a sense line, to an addressed bit inthe memory array and causes a write operation to be applied to theaddressed bit. A second input is received. This causes an application oflow power, via said sense line, to the addressed bit and causes a readoperation on the addressed bit. The sense line is used to read and writethe addressed bit.

[0015] In one embodiment, the present invention provides a circuit forwriting data bits to a memory array comprising a power source forproviding voltage potential and current to said circuit and coupledthereto, an input line for receiving inputted data bit values is coupledto a logic inverter, a plurality of first transistors having first leadscoupled to the input line, a plurality of second transistors havingfirst leads coupled to an output of the logic inverter, a plurality ofsense lines coupled to other leads of the first and the second pluralityof transistors and coupled to the memory array, a plurality of senseamplifiers coupled to other leads of the first and the second pluralityof transistors, and a plurality of address lines coupled to the memoryarray and coupled to the sense lines enabling writing of said data bitto an addressed bit of said memory array.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and form apart of this specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention:

[0017]FIG. 1 is a block diagram of a data storage device configured withan interface card which is insertable in an electronic device, inaccordance with one embodiment of the present invention.

[0018]FIG. 2 is a block diagram of a data storage device configured asinsertable into a receiving slot of an electronic device, in accordancewith one embodiment of the present invention.

[0019]FIG. 3 is an illustrated perspective of a memory array of a datastorage device, in accordance with one embodiment of the presentinvention.

[0020]FIG. 4 is an illustrated schematic diagram of a portion of thememory cells of the memory array of the data storage device of FIG. 3.

[0021]FIG. 5 is an illustrated schematic diagram of a single memory cellof the memory array of FIG. 3 and FIG. 4.

[0022]FIG. 6 is an illustrated circuit diagram of a memory array, inaccordance with one embodiment of the present invention.

[0023]FIG. 7 is an illustration of a memory array addressing circuit, inaccordance with one embodiment of the present invention.

[0024]FIG. 8 is an illustrated schematic diagram of a circuit forwriting a data bit, in accordance with one embodiment of the presentinvention.

[0025]FIG. 9 is a flowchart of steps in a method for writing data bitsto a memory array.

MODE(S) FOR CARRYING OUT THE INVENTION

[0026] A method and apparatus for writing data bits to a memory array isdescribed. In one embodiment, the memory array is a cross-point diodememory array. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be obvious, however, toone skilled in the art that the present invention may be practicedwithout these specific details. In other instances, well-knownstructures and devices are shown in block diagram form in order to avoidobscuring the present invention.

[0027] The present invention is discussed primarily in the context ofwriting data bits in a memory array of a data storage device such as aflash memory unit, which can be used in conjunction with a handheld,portable, desktop, or workstation computer system. However, it isappreciated that embodiments of the present invention are well suited tobe implemented and used with other types of memory arrays that can beutilized in other electronic devices, e.g., digital cameras, digitalvideo cameras, MP3 players, portable CD players, and the like. It shouldbe further be appreciated that the present invention is also well suitedfor use in other electronic devices such as printers, electronic books,and the like. In fact, embodiments of the present invention are wellsuited to be utilized with nearly any memory array of nearly anyelectronic or computer device and/or system that is configured withwrite-once memory functionality and/or rewriteable memory functionality.

[0028] It should be appreciated that the acronym PIRM, which representsthe term permanent inexpensive rugged memory, will be used throughoutthis disclosure. It is further appreciated that the term permanent, inthe acronym PIRM, refers to memory that is permanent until changed.

[0029] It should also be appreciated that in the following disclosure,the term “data” may represented in a variety of ways, dependent upon thecontext thereof. In one example, in a memory cell, data may represent avoltage level, a magnetic state, or an electrical resistance. In anotherexample, during transmission, data may represent an electrical currentor a voltage signal. Additionally, data may represent what is primarilybinary and for convenience, may be equated to states of zero (0) and one(1). It should, however, be appreciated that the binary states mayrepresent different voltages, currents, resistances, or the like.

[0030] It should be further appreciated that the term, layerelectronics, in this disclosure, is used to describe all the functionsin addition to the basic cross-point memory that are performed on thePIRM layers. These functions include de-multiplexing (addressing),multiplexing (sensing), and the write-enable function. The processes offabricating a PIRM and the related layer electronics are described inmore detail in the co-pending U.S. patent application Ser. No. ______,entitled “Fabrication Techniques for Addressing Cross-Point Diode MemoryArrays”, by C. Taussig and R Elder, Attorney/HP docket numberHP-10002972-1, and which is hereby incorporated by reference.

[0031] The process of addressing and sensing of a cross-point diodememory array of a PIRM is described in more detail in co-pending U.S.patent application Ser. No. ______, entitled “A Method of Addressing andSensing a Crosspoint Diode Memory Array,” by C. Taussig and R Elder,Attorney/HP docket number HP-10002971-1, and which is herebyincorporated by reference.

[0032] In another embodiment, a cross-point diode memory array may beaccessed in a parallel manner. The process of parallel accessing of across-point diode memory array is described in more detail in theco-pending U.S. patent application Ser. No. ______, entitled “ParallelAccess of Cross-Point Diode Memory Arrays”, by C. Taussig and R. Elder,Attorney/HP docket number HP-10002595-1, and which is herebyincorporated by reference.

[0033]FIG. 1 shows an illustrated block diagram of a PIRM (permanentinexpensive rugged memory) 9 upon which embodiments of the presentinvention may be practiced. In the present embodiment, PIRM 9 is shownto be removeably coupled to an industry standard interface card 5. Inone embodiment, interface card 5 is a PCMCIA card. In anotherembodiment, interface card 5 is a Compact Flash card. Interface card 5is shown, in one embodiment, to be removeably coupled to device 1 viabus 6. Bus 6 provides a communication pathway between device 1 andinterface card 5. In one embodiment, interface control circuit 3 iscoupled with bus 6 and PIRM 9 via internal bus 7. Internal bus 7provides a communication pathway between interface control circuit 3 andPIRM 9. Interface control circuit 3 comprises controlling, interfacing,detecting, and error correction coding (ECC) circuitry, and the like,for each PIRM 9 when it is received in interface card 5. PIRM 9 providescircuitry for write-to data storage, which includes some detection,write enabling, and addressing functions.

[0034]FIG. 2 shows a PIRM 9, upon which embodiments of the presentinvention may be practiced, removeably coupled to a device 1 via aninterface connector 4, in another embodiment of the present invention.In one embodiment, PIRM 9 is adapted to be inserted into device 1 in adirection as indicated by arrow 2. PIRM 9 is analogous to PIRM 9 ofFIG. 1. Device 1 is shown to have disposed therein interface controlcircuit 3 which is communicatively coupled thereto and coupled tointerface connector 4 via bus 6. It should be appreciated that interfacecontrol circuit 3 is analogous to interface control circuit 3 of FIG. 1.Bus 6 provides a communication pathway between interface control circuit3 and interface connector 4. PIRM 9 is adapted to be removeably coupledto interface connector 4, when a PIRM 9 is received by device 1 througha slot or opening disposed upon an external surface thereof. In anotherembodiment, PIRM 9 may be coupled to device 1 via a interface cable,e.g., a serial cable, a IEEE 1394 Firewire, a USB cable, and the like.

[0035] Still referring to FIG. 2, some newer printers, digital cameras,and handheld computer systems are configured with external slots whichare adapted to receive digital storage devices, such as PIRM 9 that isshown as inserted into device 1. Accordingly, utilizing this type ofdigital data storage to exchange data or information between devices soequipped is a simple and easy process. In one embodiment, PIRM 9 isconfigured as an SD (secure digital) card. In another embodiment, PIRM 9is configured as an MMC (multi media card).

[0036] It should be appreciated that write-once memory means that datacan be effectively written to the memory once, and nearly unchangeablethereafter. For example, many examples of write-once memories areoriginally set at first binary state, which may be represented by abinary data value of zero (0). During a write process, writing toselected memory cells will change the first binary state to a secondbinary state, represented by a binary value of one (1). Commonly, oncethe selected memory cells are changed from a first state (0) to a secondstate (1), that change in state cannot be reversed. Conversely, if amemory cell has not been changed from a zero to a one, then that memorycell may have its state altered at a later time. However, because of theprevious writing which altered selected memory cells, remaining memorycells still in the first state may not be arbitrarily changed.

[0037] It should be further appreciated that rewriteable memory meansthat the memory may be written to, and then re-written many times.Unlike RAM (random access memory), a type of rewriteable memory, therewriteable memory described in the following does not lose its datawhen unpowered.

[0038]FIG. 3 is an illustration showing a PIRM 9, in one embodiment ofthe present invention. The top layer 349 shows a cross-point diodememory array 325, coupled with addressing circuits 370. Addressingcircuits 370 are coupled with input/output (I/O) leads 360 whichterminate at the edge of the substrate of each layer and are coupled tocontact elements 355 thereby effectively connecting each additionallayer 350. Each additional layer 350 has disposed upon the substrate across-point diode memory array 325, addressing circuits 370, and I/Oleads 360.

[0039] Still referring to FIG. 3, shown also is an array 330, a portionof cross-point diode memory array 325 of layer 349. Array 330 will bemore thoroughly shown and described in FIG. 4.

[0040] It should be appreciated that although FIG. 3 depicts fivelayers, this only to more clearly illustrate the components andcircuitry disposed upon each layer, and should not be construed as alimitation to the number of layers that may comprise a cross-pointmemory.

[0041]FIG. 4 is an exploded view of array 330 of cross-point diodememory array 325 of FIG. 3. Array 330 comprises a matrix of row lines300 and column lines 301 with a memory element/cell 320 at therow/column intersections. Memory element/cell 320 is at the intersectionof exactly one row and one column line and is shown is greater detail inFIG. 5

[0042]FIG. 5 is an expanded illustration of memory element/cell 320.Memory element/cell 320 is shown to be comprising a fuse element 322coupled in series to a memory element/cell diode 321. The fuse element322 provides the actual data storage effect of the memory element 320.Diode 321 facilitates the addressing of the memory element/cell 320 byutilizing row lines 300 and column lines 301.

[0043] In one embodiment of the present invention, the operation ofmemory element/cell 320 is as follows. Subsequent to fabrication ofmemory elements 320, each memory element 320 has a fuse element 322which is conductive. The conductive state of fuse element 322 isrepresentative of a first binary state, such as a data value of zero(0). To write to memory array 325, each memory element/cell 320 in whichit is desired to store a second binary state, such as a data value ofone (1), is addressed utilizing row and column lines and fuse element322 is thereby blown, placing it in a non-conductive state. Blowing fuseelement 322 is, in most circumstances, a non-reversible process, whichmakes memory array 325 a write-once data storage, as discussed above.Writing to memory element/cell 320 can be accomplished by applying apredetermined energy to memory element 320 via a selected row line 300and a selected column line 301. It should be appreciated that the energybeing applied to memory element/cell 320 must be sufficient to blow thefuse element 322 which intersects the selected row and column lines.

[0044] In another embodiment of the present invention, while the abovedescription utilizes a fuse element 322 which is fabricated in alow-resistance state and subsequently, when written to, is altered to ahigh-resistance state, it is equivalently possible to provide a memoryelement 320 which utilize an anti-fuse. An anti-fuse operates converselyto a fuse. An anti-fuse is, at fabrication, in a high-resistive stateand blown to create a low-resistive state. The anti-fuse in each memoryelement 320, when memory element 320 is so configured, is also formed inseries with a memory element diode 321, whose function is necessarysubsequent to the blowing of the anti-fuse.

[0045] It should be appreciated that embodiments of the presentinvention can be readily utilized with alternative fuses that areconfigured for utilization as both a fuse and an anti-fuse. This type offuse can written to many times, e.g., changing from a fuse to ananti-fuse and back again to a fuse, as required.

[0046] It should be appreciated that during the reading of bit values, 1or 0, the reading must be gentle enough so as not to cause a change inthe state of the bit. It should further be appreciated that when writingdata bits, it is necessary to ensure that there is sufficientvoltage/power/current to ensure the proper state of the data bit. In oneembodiment, sense lines, e.g., sense lines 302 and 303 (FIG. 6) areutilized to read the state of the addressed bit, as well to change thestate of the bit, as when writing to the addressed bit.

[0047]FIG. 6 is an illustrated schematic diagram of a memory circuitwherein a cross-point memory array 325 is disposed, as shown in FIG. 3.In one embodiment of the present invention, writing data bits to amemory element 320 within a cross-point diode memory array 325 isimplemented while providing power conservation.

[0048] Still referring to FIG. 6, cross-point memory array 325 is formedby a matrix of row lines (electrodes) 300 and column lines (electrodes)301. The row lines 300 and column lines 301 extend from cross-pointdiode memory array 325 through row address lines (circuitry) 304, rowsense line 303, column address lines (circuitry) 305, and column senseline 302, respectively, in one embodiment of the present invention. Inone embodiment, column lines 301 are arranged such that the powerconnections to the ends of column lines 301 are in stripes (groups of,e.g., three) and are labeled C1, C2, and C3, respectively. In oneembodiment, row lines 300 are arranged such that the power connectionsto the ends of the row lines are in stripes (groups of e.g., three) andare labeled R1, R2, R3, respectively. Therefore, when writing to amemory cell, for example memory element/cell 320 within sub array 330,only those row and column lines within the appropriate stripe are toreceive power. Accordingly, in this example, when writing to memory cell320 which is in sub array 330, only row stripe R1 and column stripe C1receive power such that only sub array 330, which contains memoryelement 320, is energized.

[0049] It should be appreciated that had another memory elementdisposed, for example, in sub array 340, in the lower right corner ofcross-point memory array 325, then only row stripe R3 and column stripeC3 would receive power such that R3 and C3 would be energized. It shouldbe further appreciated that by only activating those stripes whichcontain the memory elements to which the writing of a data bit isdirected, a substantial reduction in power consumption is realized.

[0050]FIG. 7 is an illustrated schematic diagram of a portion of awrite-to memory array 325 of which memory element 320 is part. Memoryelement 320, which comprises fuse element 322 and diode 321 as shown inFIG. 5, is coupled between a row line 300 and a column line 301. Rowaddress lines 304 are coupled to row lines 300 at appropriate pointsthrough addressing decoding diodes, and column address lines 305 arecoupled to column lines 301 in an analogous manner. Resistor 306 isinterposed between column line 301 and pull-up voltage, +V, and coupledtherewith. Resistor 307 is interposed between row line 301 and pull-downvoltage, −V and coupled therewith. Row address lines 304 are coupled toa plurality of row address diodes 308. Row address diodes 308 have theiranodes coupled to the row address line 304 and their cathodes coupled torow lines 300 and are controlled by the voltage of the row address lines304. Column address lines 305 are coupled to a plurality of columnaddress diodes 309. Column address diodes 309 have their cathodescoupled to column address lines 305 and their anodes are coupled tocolumn lines 301, and are controlled by the voltage of column addresslines 305.

[0051] Still with reference to FIG. 7, column electrode 301 is high onlywhen column address input voltages CD1, CD2, and CD3 are high (+V). Rowelectrode 300 is low only when row address input voltages RD1, RD2, andRD3 are low (−V). Therefore, when row address inputs RD1, RD2, and RD3all apply anode voltages of −V to the diodes 308 and column addressinputs CD1, CD2, and CD3 all apply cathode voltages of +V to diodes 309,then memory element 320 is selected. It should be appreciated thatalthough only three-input circuits are shown in FIG. 7, this writingscheme can be expanded to include either a larger or smaller number ofinputs.

[0052] Referring still to FIG. 7, it should also be appreciated that ifany one of the row address diodes is connected to a voltage near +V,then regardless of the state of the column address diodes, the memoryelement will not be forward biased. Similarly, if any one of the columnaddress diodes is connected to a voltage near −V, then the memory cellcannot be forward biased.

[0053]FIG. 8 is an illustrated schematic diagram of writing circuit 800which can be implemented in writing data bits to a PIRM memory, in oneembodiment of the present invention. Memory array portions 325A and325B, respectively, represent the column and row portions of a memoryarray 325. Data bit input line 345, which contains the data bit to bewritten and is coupled to the input of logic inverter 315, is shown tobe coupled to transistor 316A via node 362 and coupled to transistor316D via node 363. Logic inverter 315 has its output coupled totransistors 316B and 316C. In one embodiment, transistors 316A-D are MOS(metal oxide semiconductor) transistors. In another embodiment,transistors 316A-D may be of another transistor type, provided that thedifferent transistor type provides functionality analogous to a MOS typetransistor. In the present embodiment, transistors 316A-316D areequivalent.

[0054] Still referring to FIG. 8, transistor 316B is shown as having anelectrode coupled to an input of column sense amplifier 312. Transistor316C is shown to have one electrode coupled to an input of row senseamplifier 313. Row sense amplifier 313 is shown to be coupled innegative feedback. Column sense amplifier 313 is also shown to becoupled in negative feedback.

[0055] Referring still to FIG. 8, when a data bit having a binary valueof one (1) is to be written to a memory element, e.g., memory element320 of FIG. 7, via data bit input line 345, the inputted binary value ofone (1) activates transistors 316A and 316D, which thereby enablesapplying of the +V to the column sense line 302 via node 372 and alsoenables applying of the −V to the row sense line 303 via node 373.Therefore, both transistor 316A and 316D are turned on (conductive), andas such, writing of a data bit into the memory array is enabled.Further, when the data bit on line 345 is a one (1), that forces logicelement 315, as an inverter, to output a zero (0), and because of theoutputted zero (0), transistors 316B and 316C are turned off(non-conductive). Therefore nodes 372 and 373 are isolated from thesense amplifiers, 312 and 313, respectively.

[0056] Still with reference to FIG. 8, when a data bit having a binaryvalue of zero (0) is to be written to memory element 325, via data bitinput line 345, or when memory array 325 is being read, the inputtedbinary value of zero (0) at nodes 362 and 363 retain transistors 316Aand 316D in an off or non-conductive state. This also isolates nodes 372and 373 from +V and −V, respectively. The inputted zero is thenoutputted, via logic inverter 315, as a one (1), which in turn, turns ontransistors 316B and 316C, making them conductive. Conduction oftransistors 316B and 316C enables row sense line 303 to apply input torow sense amplifier 313 via node 373. It also enables column sense line302 to apply input to column sense amplifier 312 via node 372. Thiscauses nodes 372 and 373 to be held near ground, thereby disabling thewriting of data bit one (1) to memory array 325. It should beappreciated that row sense amplifier 313, by being coupled in negativefeedback, will hold node 373 at the mid-voltage. It should also beappreciated that column sense amplifier 312, by being coupled innegative feedback, will hold node 372 at the mid-voltage. Subsequently,a zero (0) remains in memory array 325, by virtue of not writing a one.

[0057] It is further appreciated that in another embodiment of thepresent invention, logic inverter 315 could be omitted, and transistors316B and 316C could be made complimentary to the polarity of transistors316A and 316D, effecting complimentary pairs of transistors, e.g., CMOS(complimentary metal oxide semiconductors), disposed within writingcircuit 800 of FIG. 8. For example, transistors 316A and 316B wouldbecome a complimentary transistor pair and transistors 316C and 316Dwould also become a complimentary transistor pair. In this embodiment,one of each of the pairs of transistors (e.g., 316A and 316D) would bein an on-state (conductive) and the other (e.g., 316B and 316C) would bein an off-state (non-conductive), depending upon the value of thereceived inputted bit. It is also appreciated that each of thetransistors with changed polarity, such as 316B and 316C would thusperform analogously to transistors 316B and 316C coupled with logicinverter 315, as described above.

[0058]FIG. 9 is a flowchart 900 of steps performed in accordance withone embodiment of the present invention for providing a method ofwriting data bits to a crosspoint array. Flowchart 900 includesprocesses of the present invention which, in one embodiment, are carriedout by processors and electrical components under the control ofcomputer readable and computer executable instructions. The computerreadable and computer executable instructions reside, for example, indata storage features such as computer usable volatile memory (RAM)and/or computer usable non-volatile memory (ROM). However, the computerreadable and computer executable instructions may reside in any type ofcomputer readable medium. Although specific steps are disclosed inflowchart 900, such steps are exemplary. That is, the present inventionis well suited to performing various other steps or variations of thesteps recited in FIG. 9. Within the present embodiment, it should beappreciated that the steps of flowchart 900 may be performed bysoftware, by hardware or by any combination of software and hardware.

[0059] In step 902 of FIG. 9, an input is received. In one embodiment,the input is a one (1) or a zero (0). In one embodiment, the input isreceived via an input line, e.g., input line 345 of FIG. 8.

[0060] In step 904 of FIG. 9, a first input, in one embodiment a one(1), causes an application of a high power, via a sense line, e.g.,sense lines 302 and 303 of FIG. 6, to an addressed bit of a memoryarray, e.g., address bit 320 of memory array 325. The high power appliedto the addressed bit causes a write operation on the addressed bit. Thesense line is utilized to write to the addressed bit.

[0061] In step 906 of FIG. 9, a second input, in one embodiment a zero(0), causes an application of a low power, via a sense line, e.g., senselines 302 and 303 of FIG. 6, to an addressed bit of a memory array,e.g., address bit 320 of memory array 325. The low power applied to theaddressed bit causes a read operation on the addressed bit. The senseline is utilized to write to the addressed bit.

[0062] It is appreciated that the order in which the first and secondinputs are received are arbitrary, such that the second input can bereceived prior to receiving the first input, or vice-versa.

[0063] The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical application,to thereby enable others skilled in the art to best utilize theinvention and various embodiments with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the invention be defined by the Claims appended hereto and theirequivalents.

What is claimed is:
 1. A method for writing a data bit to a memoryarray, said method comprising: receiving a first input causing anapplication of high power, via a sense line, to an addressed bit in saidmemory array and causing a write operation on said addressed bit, andreceiving a second input causing an application of low power, via saidsense line, to said addressed bit and causing a read operation on saidaddressed bit, such that said sense line is used to read and write saidaddressed bit.
 2. The method as recited in claim 1 further comprisingaddressing said addressed bit, via a plurality of address linescomprising a plurality of column address lines and a plurality of rowaddress lines, provided said plurality of column address lines are highand said plurality of row address lines are low.
 3. The method asrecited in claim 1 further comprising isolating a second plurality ofswitches, subsequent to the receiving of said first input, wherein saidsecond plurality of switches are in a non-conductive state.
 4. Themethod as recited in claim 1 further comprising isolating a firstplurality of switches, subsequent to the receiving of said second input,wherein said first plurality of switches are in a non-conductive state.5. The method as recited in claim 1 further comprising holding avoltage, determined at a plurality of nodes coupled to a first pluralityof switches and a second plurality of switches, at a mid-voltage level,such that a zero state of said addressed bit is unchanged, saidmid-voltage level provided by a plurality of sense amplifiers, coupledto said sense line.
 6. The method as recited in claim 1 furthercomprising changing a state of said addressed bit from a high resistancestate to a low resistance state when said addressed bit is an anti-fuse.7. The method as recited in claim 1 further comprises changing a stateof said addressed bit from a low resistance state to a high resistancestate when said addressed bit is a fuse.
 8. The method as recited inclaim 2 further comprising utilizing power-striping as part of saidaddressing of said addressed bit.
 9. A circuit for writing a data bit toa memory array comprising: a power source for providing voltagepotential and current to said circuit and coupled thereto; a input linefor receiving inputted data bit values and coupled to a logic inverter;a plurality of first transistors having first leads coupled to saidinput line; a plurality of second transistors having first leads coupledto an output of said logic inverter; a plurality of sense lines coupledto other leads of said first and said second plurality of transistorsand coupled to said memory array; a plurality of sense amplifierscoupled to other leads of said first and said second plurality oftransistors; and a plurality of address lines coupled to said memoryarray and coupled to said sense lines, enabling writing of said data bitto an addressed bit of said memory array.
 10. The circuit of claim 9wherein said first plurality of transistors comprise a first transistorand a fourth transistor, and wherein a third lead of said firsttransistor is coupled to a higher potential voltage coupled to saidcircuit, and wherein a second lead of said first transistor is coupledto one of said plurality of sense lines.
 11. The circuit of claim 10wherein a second lead of said fourth transistor is coupled to a lowerpotential voltage coupled to said circuit, and wherein a third lead ofsaid fourth transistor is coupled to one of said sense lines.
 12. Thecircuit of claim 9 wherein said plurality of second transistors comprisea second transistor and a third transistor, and wherein a third lead ofsaid second transistor is coupled to one of said plurality of senselines, and wherein a second lead of said second transistor is coupled toa input of one of said plurality sense amplifiers.
 13. The circuit ofclaim 12 wherein a third lead of said third transistor is coupled to aninput of one of said sense amplifiers and wherein a second lead of saidthird transistor is coupled to one of said sense lines.
 14. The circuitof claim 9 wherein said plurality of sense lines comprise a row senseline and a column sense line and wherein said row sense line is coupledto a second lead of a third transistor of said second plurality oftransistors and wherein said row sense line is coupled to a third leadof a fourth transistor of said first plurality of transistors.
 15. Thecircuit of claim 14 wherein said column sense line is coupled to asecond lead of a first transistor of said first plurality of transistorsand wherein said column sense line is coupled to a third lead of asecond transistor of said second plurality of transistors.
 16. Thecircuit of claim 9 wherein said plurality of sense amplifiers comprisean column sense amplifier and a row sense amplifier and wherein an inputof said column sense amplifier is coupled to a second lead of a secondtransistor of said second plurality of transistors.
 17. The circuit ofclaim 16 wherein an input of said row sense amplifier is coupled to athird lead of a third transistor of said second plurality oftransistors.
 18. The circuit of claim 9 wherein said plurality ofaddress lines comprise a plurality of row address lines and a pluralityof column address lines, and when said plurality of row address linesare of a low voltage and when said plurality of column address lines areof a high voltage, addressing of said addressed bit of said memory arrayis enabled.
 19. The circuit of claim 9 wherein said writing of said databit to said addressed bit of said memory array changes the state of saidaddressed bit from a high resistance state to a low resistance statewhen said addressed bit is an anti-fuse, and wherein writing of saiddata bit to said addressed bit of said memory array changes the state ofsaid addressed bit from a low resistance state to a high resistancestate when said addressed bit is a fuse.
 20. The circuit of claim 18wherein power striping is used as part of said addressing of saidaddressed bit.
 21. A circuit for writing a data bit to an addressed bitin a memory array comprising: a power source for providing voltagepotential and current to said circuit and coupled thereto; a data bitinput line for receiving inputted data bit values and coupled to a logicinverter; a first transistor having a first lead coupled to said datainput line and a second lead coupled to a column sense line and a thirdlead coupled to a positive voltage, said positive voltage coupled tosaid circuit; a second transistor having a first lead coupled to anoutput of said logic inverter and a second lead coupled to an input of acolumn sense amplifier and a third lead coupled to said column senseline; a third transistor having a first lead coupled to said output ofsaid logic inverter and a second lead coupled to a row sense line and athird lead coupled to an input of a row sense amplifier; and a fourthtransistor having a first lead coupled to said input line and a secondlead coupled to a negative voltage and a third lead coupled to said rowaddress line, enabling writing of said data bit to said addressed bit.22. The circuit of claim 21 further comprising a plurality of columnaddress lines coupled to said memory array and coupled to said columnsense line and a plurality of row address lines coupled to said rowsense line, and wherein addressing said addressed bit of said memory isenabled when said plurality of column address are of a positive voltageand when said plurality of said row address lines are of a negativevoltage.
 23. The circuit of claim 21 wherein said addressed bit iswritten to a one state when said state of said addressed bit is changedfrom a high resistance state to a low resistance state when saidaddressed bit is an anti-fuse and when said state of said addressed bitis changed from a low resistance state to a high resistance state whensaid addressed bit is a fuse.
 24. The circuit of claim 21 wherein saidaddressed bit is written to a zero when said row sense amplifier,coupled in feedback, and said column sense amplifier, coupled infeedback, disable writing of one bit by holding said voltage potentialat a mid-voltage, such that said addressed bit remains a zero by notwriting a one bit.
 25. The circuit of claim 22 wherein power striping isutilized in part of said addressing said addressed bit.
 26. A circuitfor writing a data bit to a memory array comprising: a power source forproviding voltage potential and current to said circuit and coupledthereto; a input line for receiving inputted data bit values and coupledto said memory array; a plurality of first transistors having firstleads coupled to said input line; a plurality of second transistorshaving first leads coupled to said input line, and wherein saidplurality of second transistors are complimentary to the polarity ofsaid plurality of first transistors; a plurality of sense lines coupledto other leads of said first and said second plurality of transistorsand coupled to said memory array; a plurality of sense amplifierscoupled to other leads of said first and said second plurality oftransistors; and a plurality of address lines coupled to said memoryarray and coupled to said sense lines, enabling writing of said data bitto an addressed bit of said memory array.
 27. The circuit of claim 26wherein said first plurality of transistors comprise a first transistorand a fourth transistor, and wherein a third lead of said firsttransistor is coupled to a higher potential voltage coupled to saidcircuit, and wherein a second lead of said first transistor is coupledto one of said plurality of sense lines.
 28. The circuit of claim 27wherein a second lead of said fourth transistor is coupled to a lowerpotential voltage coupled to said circuit, and wherein a third lead ofsaid fourth transistor is coupled to one of said sense lines.
 29. Thecircuit of claim 26 wherein said plurality of second transistorscomprise a second transistor and a third transistor, and wherein a thirdlead of said second transistor is coupled to one of said plurality ofsense lines, and wherein a second lead of said second transistor iscoupled to a input of one of said plurality sense amplifiers.
 30. Thecircuit of claim 29 wherein a third lead of said third transistor iscoupled to an input of one of said sense amplifiers and wherein a secondlead of said third transistor is coupled to one of said sense lines. 31.The circuit of claim 26 wherein said plurality of sense lines comprise arow sense line and a column sense line and wherein said row sense lineis coupled to a second lead of a third transistor of said secondplurality of transistors and wherein said row sense line is coupled to athird lead of a fourth transistor of said first plurality oftransistors.
 32. The circuit of claim 31 wherein said column sense lineis coupled to a second lead of a first transistor of said firstplurality of transistors and wherein said column sense line is coupledto a third lead of a second transistor of said second plurality oftransistors.
 33. The circuit of claim 26 wherein said plurality of senseamplifiers comprise an column sense amplifier and a row sense amplifierand wherein an input of said column sense amplifier is coupled to asecond lead of a second transistor of said second plurality oftransistors.
 34. The circuit of claim 33 wherein an input of said rowsense amplifier is coupled to a third lead of a third transistor of saidsecond plurality of transistors.
 35. The circuit of claim 26 whereinsaid plurality of address lines comprise a plurality of row addresslines and a plurality of column address lines, and when said pluralityof row address lines are of a low voltage and when said plurality ofcolumn address lines are of a high voltage, addressing of said addressedbit of said memory array is enabled.
 36. The circuit of claim 26 whereinsaid writing of said data bit to said addressed bit of said memory arraychanges the state of said addressed bit from a high resistance state toa low resistance state when said addressed bit is an anti-fuse, andwherein writing of said data bit to said addressed bit of said memoryarray changes the state of said addressed bit from a low resistancestate to a high resistance state when said addressed bit is a fuse. 37.The circuit of claim 35 wherein power striping is used as part of saidaddressing of said addressed bit.
 38. A system for writing a data bit toa memory array, said method comprising: means for receiving a firstinput causing an application of high power to an addressed bit in saidmemory array, via a sense line, and causing a write operation on saidaddressed bit, and means for receiving a second input causing anapplication of low power to said addressed bit, via said sense line, andcausing a read operation on said addressed bit, such that said senseline is used to read and write said addressed bit.
 39. The system asrecited in claim 38 further comprising a means for addressing saidaddressed bit, via a plurality of address lines comprising a pluralityof column address lines and a plurality of row address lines, providedsaid plurality of said column address lines are high and said pluralityof said row address lines are low.
 40. The system as recited in claim 38further comprising means for isolating a second plurality of switches,subsequent to the receiving of said first input, wherein said secondplurality of switches are in a non-conductive state.
 41. The system asrecited in claim 38 further comprising means for isolating a firstplurality of switches, subsequent to the receiving of said second input,wherein said first plurality of switches are in a non-conductive state.42. The system as recited in claim 38 further comprising means forholding a voltage, determined at a plurality of nodes coupled to a firstand a second plurality of switches, at a mid-voltage level, such that azero state of said addressed bit is unchanged.
 43. The system as recitedin claim 38 further comprising means for changing a state of saidaddressed bit from a high resistance state to a low resistance statewhen said addressed bit is an anti-fuse.
 44. The system as recited inclaim 38 further comprises means for changing a state of said addressedbit from a low resistance state to a high resistance state when saidaddressed bit is a fuse.
 45. The system as recited in claim 39 furthercomprising means for utilizing power-striping as part of said addressingof said addressed bit.